Interaction of common variants of FTO gene and Dietary Inflammatory Index on obesity measures: Tehran Lipid and Glucose Study.

Background: This study aimed to examine the interaction of Dietary Inflammatory Index (DII) and fat mass and obesity-associated gene (FTO) single-nucleotide polymorphisms (SNPs) on change in obesity measures. Methods: A total of 4480 participants from the Tehran Lipid and Glucose Study were selected. DII was calculated using a Food Frequency Questionnaire. The FTO SNPs rs8050136, rs14211085 and rs1121980 were selected. Changes in obesity measures were calculated. Results: In individuals with risk allele of FTO SNP rs8050136, greater adherence to DII was associated with increased odds of higher waist circumference (WC) (OR, Q1-Q4: 1, 0.87, 0.88, 0.94; P trend=0.01), but deceased odds of waist to hip ratio (WHR) (OR, Q1-Q4: 1, 0.85, 0.76, 0.70; P trend=0.01). Moreover, higher score of DII was significantly related to elevated odds of having high Visceral Adiposity Index (VAI) in individuals with wild-type genotype of FTO SNPs. For changes in WC, a significant interaction was identified between FTO rs1421085 and DII; the second quartile of DII was associated with increased odds of having a high WC in carriers of wild variant (TT genotype) of rs1421085 (OR 1.43; 95% CI 1.04 to 1.97), but not in individuals with risk allele of this SNP (TC CC). Although there are significant relationships between SNPs or genetic risk score and change in WHR or VAI, but there is no significant interaction between FTO SNPs and DII regarding change in body mass index, WHR and VAI. Conclusions: There may be an interactive effect between DII and the FTO rs1421085 genotypes on change in WC.

Dietary diversity modifies the association between FTO polymorphisms and obesity phenotypes.

The current study aimed to evaluate the interaction of the dietary diversity score (DDS) and FTO polymorphisms concerning obesity phenotypes. The 4480 subjects of this cohort study were selected. The polymorphisms rs1121980, rs14211085 and rs8050136 were selected and genotyped. The weighted method was used to calculate the genetic risk score (GRS). Obesity marker changes were calculated. Those with minor allele carriers of rs1121980 had lower body mass index changes (Q1: 1.58 ± 0.60 vs. Q4: 0.13 ± 0.59) and visceral adiposity index (VAI) (Q1: -0.00 ± 0.02 vs. Q4: -0.04 ± 0.02) when they had higher DDS (P interaction = 0.05). Carriers of the minor allele of rs8050136 had significant VAI change across DDS quartiles (Q1: -0.01 ± 0.02 vs. Q4: -0.02 ± 0.02, P interaction = 0.05). No significant interaction was found between the GRS and DDS on general obesity. The pattern of dietary diversity may have a mediatory role in improving obesity markers in subjects with a more genetic predisposition to adiposity.